Bio Chapter 13 Flashcards
Why is the white eye phenotype always observed in males
carrying the white eye allele?
a. Because the trait is dominant
b. Because the trait is recessive
c. Because the allele is located on the X chromosome and
males have only one X
d. Because the allele is located on the Y chromosome and
only males have Y chromosomes
Because the allele is located on the X chromosome and
males have only one X
Dosage compensation is needed to
a. balance expression from autosomes relative to sex
chromosomes.
b. balance expression from two autosomes in a diploid cell.
c. balance expression of sex chromosomes in both sexes.
d. inactivate female-specific autosomal chromosomes
balance expression of sex chromosomes in both sexes.
Color blindness is caused by a sex-linked recessive gene. If
a woman whose father was color blind marries a man with
normal color vision, what percentage of their children will be
color blind?
a. 100% c. 25%
b. 50% d. 0%
25%
What percentage of the sons of the couple described in the previous question will be color blind?
a. 100% c. 25%
b. 50% d. 0%
50%
Genes that lie very close to each other on a chromosome
a. segregate together. c. assort independently.
b. cross over frequently. d. form chiasmata
segregate together
Mendel did not examine plant height and pod shape in his
dihybrid crosses. The genes for these traits are very close
together on the same chromosome. What would Mendel have
found if he had studied these two traits in a dihybrid cross?
a. The ratio in the F2 generation would have been 9:3:3:1.
b. The phenotypic ratio in the F2 generation would have been
3:1, but the genotypic ratio would have been 1:2:1.
c. The ratio would have been skewed from the expected
because of linkage.
d. He would not have been able to set up a cross for these two
traits, because they are found on the same chromosome.
The ratio would have been skewed from the expected
because of linkage
The map distance between two genes is determined by the
a. recombination frequency.
b. frequency of parental types.
c. ratio of genes to length of a chromosome.
d. ratio of parental to recombinant progeny
recombination frequency.
As real genetic distance increases, the distance calculated by
recombination frequency becomes an
a. overestimate due to multiple crossovers that cannot be scored.
b. underestimate due to multiple crossovers that cannot be
scored.
c. underestimate due to multiple crossovers adding to
recombination frequency.
d. overestimate due to multiple crossovers adding to
recombination frequency
underestimate due to multiple crossovers that cannot be
scored.
In a plant, the genes for seed color and seed shape are located on the same chromosome. Yellow seeds are dominant to green seeds, and round seeds are dominant to wrinkled seeds. A plant heterozygous for both genes is test-crossed
to a homozygous recessive plant, and the following data are obtained:
green, wrinkled 645
green, round 36
yellow, wrinkled 29
yellow, round 590
How far apart are the two genes?
a. 2.5 map units
c. 50 map units
b. 5 map units
d. 95 map unit
5 map units
Nondisjunction
a. can occur in meiosis I or meiosis II.
b. can be detected in a karyotype.
c. can occur in sex chromosomes and autosomes.
d. All of the above
All of the above
During the process of spermatogenesis, a nondisjunction event
that occurs during the second division would be
a. worse than the first division because all four meiotic
products would be aneuploid.
b. better than the first division because only two of the four
meiotic products would be aneuploid.
c. the same outcome as the first division with all four
products aneuploid.
d. the same outcome as the first division as only two products
would be aneuploid.
better than the first division because only two of the four
meiotic products would be aneuploid
Why is nondisjunction more common in oogenesis than in
spermatogenesis?
a. Eggs are formed daily, and this fast rate of production
means more chances for problems
b. Egg development starts in the fetus, allowing time for
potential mutations that lead to errors in cell division to
accumulate.
c. Eggs are diploid and sperm are haploid.
d. Oogenesis and spermatogenesis have equivalent rates of
nondisjunction.
Egg development starts in the fetus, allowing time for
potential mutations that lead to errors in cell division to
accumulate
Which of the following CANNOT be determined from
pedigree analysis?
a. Whether a trait is dominant or recessive
b. Whether a trait is sex-linked or autosomal
c. The chance of future generations inheriting a trait
d. The type of mutation leading to a disease state
The type of mutation leading to a disease state
The sickle-cell trait is recessive. This means
a. an individual who is heterozygous makes all normal
hemoglobin protein.
b. an individual must have two abnormal copies of the
hemoglobin gene to exhibit the trait.
c. the condition is not very common in the human population.
d. anyone affected by the disease must have a parent who is
also affected.
an individual must have two abnormal copies of the
hemoglobin gene to exhibit the trait.
The ability to distinguish between the colors red and green is
eliminated by a hereditary defect known as red-green color
blindness. Below is a pedigree for red-green color blindness
through four generations of a family.
The results of this pedigree indicate that red-green color
blindness is caused by
a. a single autosomal recessive gene.
b. a single autosomal dominant gene.
c. a single sex-linked recessive gene.
d. a single sex-linked dominant gene.
a single sex-linked recessive gene.
